The field of the disclosure relates generally to gas turbine engines and, more particularly, to a method and system for varying a core cowl vent nozzle area.
In at least some known aircraft engine systems, an inner casing at least partially surrounds a core engine. A core cowl extending aftward from the inner casing defines a cowl nozzle or cowl vent area defined between the core cowl and an engine primary (core) nozzle. Pressurized gas is exhausted through this cowl nozzle, which can provide propulsive thrust to the aircraft. The pressurized gas that is piped through the core cowl and exhausted out the cowl vent may be used to cool accessories located outside the engine casing but within the core cowl. The core cowl is typically fabricated as a single, static component, dimensioned such that the cowl nozzle has a maximum area necessary during “worse-case” conditions, such as high-temperature take-off or certain hold conditions. However, this cowl vent area is often larger than needed during “better-case” conditions, such as cruise, such that the cooling air to the accessories may not be needed, and the cowl nozzle does not provide enough thrust and may even generate drag.